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in substantially its present form about twenty years ago by Mr. John Thompson, of 
East Boston, who was then connected with the Eastern Railroad in the capacity of 
master mechanic. It was tried thoroughly by him at that time, but was abandoned 
for the reason that a comparatively few miles run would fill up the smoke-arch with 
sparks and so interfere with the draft that the capacity of the boiler to generate steam 
in sufficient quantities to supply the .wants of the engine wa3 destroyed. The small 
furnaces used at that time and the powerful artificial draft made necessary thereby 
produced this result. 
As I stated in a former paragraph, the introduction of steel for rails and tires made 
the use of larger boilers possible, and with their introduction came the successful use 
of the spark-consuming and arresting devices described. The railroad with which I 
am connected has had these appliances in use on a limited number of engines for the 
past two years, and in no case has a forest or other fire been set by them, and if kept 
in proper order I believe they are absolutely safe. 
In conclusion, I wish to say that careful and intelligent manipulation of the fire by 
the fireman is imperative, and will do more to prevent the formation of smoke than 
any mechanical contrivances. 
Upon solicitation the following letter on the same subject was received 
by the Department : 
IMPOETANCE OF SPARK-AEEESTEES. 
Chicago and Northwestern Railway Company, 
Department of Motive Power and Machinery, 
■ Chicago, October 27, 1886. 
Hon. Norman J. Colman, 
Commissioner of Agriculture. 
Dear Sir : I herewith beg leave to submit the following in answer to your request 
in regard to the best appliances in use on locomotives on the railways of this conn try 
for the prevention of fires on the lines of such railways, the preservation of forests, 
and all vegetation contiguous to them. It is a subject that has engaged and is, I 
believe, engaging the attention of many of the practical and scientific men of the 
day. Perhaps the subject has not yet received the attention it deserves, but I believe 
there is a growing tendency, both by railway officials and those not connected with 
railways, to solve this question ; and while I do not think we have attained perfec- 
tion, and never may attain it, I do think great improvements have been made in this 
direction within the last few years. For many years the almost universal practice 
was to use what is called the "Diamond Stack, " which is too generally known to 
need a description here. While this and its appliances may have been faulty in prin- 
ciple, or in some particulars, it has been considered the standard until within a few 
years, when to some extent it has been superseded by other appliances for arresting 
sparks, among which (and one that is meeting with the most favor) is what is known 
as the "Extended Front-end and Straight Stack." This device ditfers materially 
from the appliances used with the "Diamond Stack," both in construction and prin- 
ciple. With the "Diamond Stack" the practice usually has been to place the netting 
in the stack over a cast-iron cone or deflector, the point of discharge of the exhaust 
pipes from 8 to 12 inches above the lower row of tubes in the boiler, and between 
the top of the exhaust pipes and the bottom of the stack, an intermediate pipe made 
of a size to give the best results according to the varying conditions, and designated 
as an "extension pipe," "petticoat pipe," and by various other names, but all for 
the same purpose, although varying in construction, to equalize the draft and carry 
the cinders that would be drawn through the flues in a straight line to the point or 
center of the cone or deflector; here they would be turned downward again and 
broken up by contact with the cone or deflector, and either be burned in the bottom 
